ABSTRACT
Seedlings of eight soft red winter wheat (Triticum aestivum) cultivars were grown in an aeroponic mist box to study the effects of barley yellow dwarf virus (BYDV) on root and shoot growth and to look for differences in root and shoot growth among cultivars. The cultivars selected for the study were Caldwell, Cardinal, Clark, Howell, IL 87-2834, Tyler, and Pioneer brands 2548 and 2555. A split-plot treatment design was used, with uninfected and inoculated treatments as whole plots and cultivars as subplots. Differences among cultivars were found for most growth characteristics under both control and BYDV-infected conditions. There was a strong positive correlation between shoot and root dry weights in both the control and BYDV treatments, indicating that cultivars with vigorous shoot growth tended to have more vigorous root growth. BYDV severely reduced root length, distance from seminal root tip to the nearest lateral root, and the root to shoot ratio for all cultivars tested. The number of adventitious roots and shoot percent dry matter were increased by BYDV infection for some cultivars. Chlorosis and stunting were not observed in shoots during the 18 days of the experiment, whereas roots were visibly stunted approximately 4 days after inoculation. Results indicate that, initially, the root system is affected more severely than the shoot in BYDV-infected wheat seedlings.
